Using New Outlook on Windows for personal email, calendar, and contact management
Hello, thank you for reaching out to Microsoft Q&A.
I'm sorry you're experiencing this problem. I understand how important recovering your account is to you.
Microsoft always recommends that users have at least three verification methods. So, even if one method becomes disabled, you can prove your identity using another method.
When did you last successfully sign in to your Microsoft account? If you have not logged into your account for more than two years and it has been closed due to inactivity, you will not be able to use the Account Recovery Form to recover your account. Reference:
Microsoft account activity policy
If you no longer have your number, you will have to replace it by selecting 'I don't have any of these' and follow the prompts.
Note - Microsoft takes account security very seriously, that's why Account Recovery is an automated process with no human influence. If you don't have the correct information, you may not be able to get through account verification using the Recovery Form.
Remember to use a familiar device from which you've frequently accessed your Microsoft account, as well as a familiar location. Microsoft will review your responses and respond within 24 hours. If you are verified, instructions on how to log back into your account will be sent to you, and if you are not verified, you will need to submit the Account Recovery form again. You can do this up to 2 times every 24 hours.
See Account recovery unsuccessful article for reference